In general, toner (transfer residual toner) or the like that is not completely transferred to a medium (e.g., paper sheet) is easily left, as an unwanted substance, on the surface of an electrophotographic photosensitive member or intermediate transfer member. Such an unwanted substance degrades image quality in the subsequent image forming process, and thus needs to be removed each time.
Transfer residual toner on the surface of an electrophotographic photosensitive member or intermediate transfer member is removed by, for example, a method in which an unwanted substance is scraped off by bringing a brush-shaped or blade-shaped cleaning member into contact with the surface of an electrophotographic photosensitive member or intermediate transfer member or a method in which an unwanted substance is removed by suction. In particular, a method that uses a blade-shaped cleaning member, that is to say, a cleaning blade has been widely used because cleaning can be effectively performed with a simple structure. The cleaning blade is often composed of rubber (particularly urethane rubber) that easily provides adhesion between the cleaning blade and the surface of an electrophotographic photosensitive member or intermediate transfer member.
However, rubber is a material having a high coefficient of friction. This causes an unusual sound (blade chattering), a decrease in the capability of scraping toner due to vibration of a cleaning blade (passing toner), and a phenomenon in which a cleaning blade curls (blade curling).
PTL 1 discloses a method in which a fluorine-based or silicone-based solid lubricating component is applied to a cleaning blade to decrease the friction between the cleaning blade and an electrophotographic photosensitive member.
PTL 9 discloses a method in which a solid lubricating component is applied to a cleaning blade to decrease the friction between the cleaning blade and an intermediate transfer member.
PTLs 2 and 3 disclose methods in which a fluorocarbon resin component is contained in a surface layer of an electrophotographic photosensitive member. PTL 4 discloses a method in which a silicone resin component is contained in a surface layer of an electrophotographic photosensitive member.
PTLs 5 and 6 disclose methods in which lubricity and cleaning property are improved by forming projections and depressions on the surface of an electrophotographic photosensitive member.
PTLs 7 and 8 disclose methods in which the coefficient of friction is decreased by incorporating inorganic particles in a surface layer of an electrophotographic photosensitive member.